AB0517 IMPAIRED INTESTINAL BARRIER FUNCTION IN SLE MEASURED BY SERUM ZONULIN
Authors: J. An, Y. Wang, R. Fan, X. R. Hu, Y. Q. Liu, F. Zhang, J. Chen
Journal: Annals of the Rheumatic Diseases (2022)

Background Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease characterized with the secretion of normal autoantibodies, which leads to the involvement of multiple organs. Several observations have showed that the breakdown of immune tolerance was involved in the pathogenesis of SLE, especially the imbalance of Th17/Treg [1] , but the mechanism of the impaired immune tolerance is unknown yet. Numerous researches support that intestinal mucosal barrier is an upstream mechanism leading to impaired immune balance [2] . However, the relationship between intestinal mucosal barrier and SLE is little known. Objectives To measure the expression of serum zonulin to assess and compare the function of intestinal mucosal barrier in patients with SLE and healthy adults, and to explore the role of intestinal mucosal barrier in the pathogenesis and development of SLE. Methods 20 patients with SLE who hospitalized at the Second Hospital of Shanxi Medical University and 10 age and gender-matched healthy adults were enrolled in this study. We collected the blood sample of the patients and healthy controls to examine the function of intestinal mucosal barrier and the absolute number of Th17 and Treg cells. The level of serum zonulin was measured by ELISA to assess the function of intestinal mucosal barrier. The absolute number of Th17 cells and Treg cells was detected by flow cytometry. Disease activity indicators of patients with SLE were collected from laboratory including erythrocyte sedimentation rate (ESR, mm/h), complement 3(C3, g/l) and anti-dsDNA (IU/ml). Then we compared the expression of serum zonulin between the patients and healthy controls and analyzed the correlation of serum zonulin with Th17 cells, Treg cells and disease activity. Results The level of serum zonulin of SLE group were significantly higher than that of healthy control group (p&lt;0.05). And the expression of serum zonulin was positively correlated with the level of ESR (r=0.491, p=0.033) and anti-dsDNA, but was negatively correlated with C3 (r=-0.519, p=0.018). And the expression of serum zonulin was not correlated with the absolute number of Th17 cells and Treg cells (P&gt;0.05), but Th17 cells showed a trend of increasing with the increase of zonulin, while Treg cells showed a trend of decreasing with the increase of zonulin. Conclusion The results here showed that the level of serum zonulin,a marker of the intestinal mucosal barrier function,was up-regulated in patients with SLE, and the higher level of serum zonulin was positively correlated with the disease activity of SLE, which indicated that impaired intestinal mucosal barrier function in SLE played an important role in the development of the disease. Table 1. A summary of baseline demographics of all enrolled patients and healthy controls HC(n=10) SLE(n=20) P value Age(years) 44.1±18.8 42±12.384 P=0.76 Sex(male/female) 2/8 2/18 P=0.47 Results are expressed as the mean ± standard error. Normally distributed continuous variables were analyzed by the independent-samples Student’s t-test. Figure 1. The difference of the expression of serum Zonulin in patients with SLE and healthy controls. Statistical analyses were performed by the Mann-Whitney U test.(***P&lt;0.001) Figure 2. The correlation of disease activity with the level of serum Zonulin.Statistical analyses were performed by the Spearman correlation analysis. Figure 3. The correlation of disease activity with the level of serum Zonulin. Statistical analyses were performed by the Spearman correlation analysis. References [1]Talaat RM, Mohamed SF, Bassyouni IH, Raouf AA. Th1/Th2/Th17/Treg cytokine imbalance in systemic lupus erythematosus(SLE) patients: Correlation with disease activity[J]. Cytokine, 2015,72(2):146-153. DOI: 10.1016/j.cyto.2014.12.027 [2]Paray BA, Albeshr MF, Jan AT, Rather IA. Leaky Gut and Autoimmunity: An Intricate Balance in Individuals Health and the Diseased State[J]. Int J Mol Sci, 2020,21(24):9770.DOI: 10.3390/ijms21249770 Disclosure of Interests None declared